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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB Lounge => Topic started by: Brandon Spoon on August 08, 2015, 08:35:14 PM

Title: Powered Speakers
Post by: Brandon Spoon on August 08, 2015, 08:35:14 PM
Question:

I have (2) JBL PRX700 speakers. Should I run those at full volume?
Title: Re: Powered Speakers
Post by: Ivan Beaver on August 08, 2015, 09:06:48 PM
Question:

I have (2) JBL PRX700 speakers. Should I run those at full volume?
Why not?

The only reason you should not run the volume/level control full up is if you are trying to increase the dynamic range of the system.

Generally to get more dynamic range you turn the level control down, to lower the noise floor.

The maximum level is set by the amp inside the speaker and the sensitivity of the speaker.

HOWEVER-understand that the "volume control"  IS NOT a wattage control-just a gain control.

How much "power you push"  or the speakers are dissipating is totally dependent on how hard you are driving them with your mixer.  NOT the volume control
Title: Re: Powered Speakers
Post by: Scott Wagner on August 09, 2015, 09:53:58 AM
Question:

I have (2) JBL PRX700 speakers. Should I run those at full volume?
I tend to run mine at 12:00 - sometimes lower, for less-loud gigs.
Title: Re: Powered Speakers
Post by: Brian Jojade on August 09, 2015, 01:30:59 PM
Question:

I have (2) JBL PRX700 speakers. Should I run those at full volume?

With any speaker, it's best to turn them up to 11.  Anything less than 11 is for wussies.
Title: Re: Powered Speakers
Post by: Scott Wagner on August 09, 2015, 05:00:45 PM
I tend to run mine at 12:00 - sometimes lower, for less-loud gigs.
The REAL answer is to run them at whatever level gives you the maximum volume you will need for each particular situation. Make sure the mixer is running at a happy level (proper gain staging - let's say 0dB on analog and -12 to -18dBFS on digital). Then adjust the speaker level to give you what you need for that particular venue on that particular day. Keep in mind that the knob on the back doesn't affect the maximum level that the speaker can produce. It simply adjusts the voltage required to get to the maximum level.
Title: Re: Powered Speakers
Post by: Scott Bolt on August 09, 2015, 06:52:36 PM
It is just a personal preference, but I prefer that the speakers start clipping at about the same time as the VU meters on the mixer start tickling the red.

If I were to run my speaker inputs full hot, I would have nothing to indicate I was clipping the speakers on the mixer meters.

By setting up the gain staging like this, I have a good idea how much juice is left in the FOH.

YMMV.
Title: Re: Powered Speakers
Post by: Tim Halligan on August 09, 2015, 09:12:01 PM
...I prefer that the speakers start clipping at about the same time as the VU meters on the mixer start tickling the red.

Please tell me you mean Peak meters, or dBFS metering...not VU.

Or do you really want your speakers to go into clip from - depending on the mixer and the level calibration - -12dBFS down to -20dBFS?

Cheers,
Tim
Title: Re: Powered Speakers
Post by: Ivan Beaver on August 09, 2015, 09:21:39 PM
It is just a personal preference, but I prefer that the speakers start clipping at about the same time as the VU meters on the mixer start tickling the red.


As Tim said-I hope you do not mean actual VU meters.

I know it is "proper" to have everything in the system clip at the same time (to have the most dynamic range), but I disagree with that concept.

And others will disagree-but here is my reason.

I would prefer the amps to "run out of gas" 6dB before everything else in the system.

The "problem" with everything clipping at the same time means that it will sound REALLY REALLY bad all of a sudden-with everything clipping at once).

If the amps clip a bit earlier, then you will have a bit of "fuzz" to the sound (assuming the amps clip gracefully-not all do), before it get really bad (with everything clipping at the same time).

The other problem with trying to use the meters on the console to give an idea of how far you are away from clipping, is that many conosles do not have meters that go all the way to clip.

They may go to +10 or so, then have the clip LED (which may be at +24dBu.

That gives a range of 14dB (give or take) that you have NO idea how loud it really is.

So the whole idea of the meters giving you an idea is out the window.
Title: Re: Powered Speakers
Post by: Scott Carneval on August 10, 2015, 12:30:44 AM
Doesn't anyone use limiters anymore? You should at the very least have a peak limiter in place to prevent the amps from clipping no matter what.


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Title: Re: Powered Speakers
Post by: Ivan Beaver on August 10, 2015, 06:48:14 AM
Doesn't anyone use limiters anymore? You should at the very least have a peak limiter in place to prevent the amps from clipping no matter what.


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Actually that is a lot harder than you think.

Depending on the attack time of the limiter-you often have to set the limiter quite a bit lower in order to keep the amp out of clip.

Of course there are a bit of "depends" on this statement.

Things such as "how fast is the clip indicator on the amp", or the fact that short transients clipping are hard to detect.

YES limiters should be used-but setting them properly is not always easy.
Title: Re: Powered Speakers
Post by: Gordon Brinton on August 10, 2015, 08:36:55 AM
If you are clipping your amps, then you don't have enough rig for the gig.

But I tend to agree with Scott Wagner on reply #4
Title: Re: Powered Speakers
Post by: Jeff Hague on August 10, 2015, 09:44:42 AM
Question:

I have (2) JBL PRX700 speakers. Should I run those at full volume?

I have JBL PRX 735s, 718XLFs, 710s, 712s and 715s. As others have said, there is no 1 setting fits all. It is entirely dependent on the gig. Get your console set up first with proper gain staging and set your output where you normally would then turn up the speakers to the desired max level that you think you'll need for the performance.
Title: Re: Powered Speakers
Post by: Bob Leonard on August 10, 2015, 10:01:46 AM
Doesn't anyone use limiters anymore? You should at the very least have a peak limiter in place to prevent the amps from clipping no matter what.


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If the system is set up properly there's no reason to use a limiter. Maximum output for the system will be derived prior to clipping and prior to reaching the limits of the components being driven. And besides, only sissy's use limiters.
Title: Re: Powered Speakers
Post by: Scott Wagner on August 10, 2015, 10:41:05 AM
If the system is set up properly there's no reason to use a limiter. Maximum output for the system will be derived prior to clipping and prior to reaching the limits of the components being driven. And besides, only sissy's use limiters.
Technically, since this post is about powered speakers, everyone is using limiters - whether they know it or not.
Title: Re: Powered Speakers
Post by: Ivan Beaver on August 10, 2015, 12:53:46 PM
If the system is set up properly there's no reason to use a limiter. Maximum output for the system will be derived prior to clipping and prior to reaching the limits of the components being driven. And besides, only sissy's use limiters.
You don't do much DJ work do you Bob?????
Title: Re: Powered Speakers
Post by: Bill Hornibrook on August 10, 2015, 01:10:26 PM
Technically, since this post is about powered speakers, everyone is using limiters - whether they know it or not.
Even those of us who are passive - at least at the club level. The only power amp I've purchased in the last several years without built-in limiting was a Yamaha P7000s.
Title: Re: Powered Speakers
Post by: Scott Bolt on August 10, 2015, 09:12:04 PM
As Tim said-I hope you do not mean actual VU meters.

I know it is "proper" to have everything in the system clip at the same time (to have the most dynamic range), but I disagree with that concept.

And others will disagree-but here is my reason.

I would prefer the amps to "run out of gas" 6dB before everything else in the system.

The "problem" with everything clipping at the same time means that it will sound REALLY REALLY bad all of a sudden-with everything clipping at once).

If the amps clip a bit earlier, then you will have a bit of "fuzz" to the sound (assuming the amps clip gracefully-not all do), before it get really bad (with everything clipping at the same time).

The other problem with trying to use the meters on the console to give an idea of how far you are away from clipping, is that many conosles do not have meters that go all the way to clip.

They may go to +10 or so, then have the clip LED (which may be at +24dBu.

That gives a range of 14dB (give or take) that you have NO idea how loud it really is.

So the whole idea of the meters giving you an idea is out the window.

Good point Ivan. 

Some speakers sound very bad when they start to clip (my DSR's don't).  I think it largely depends on how the OEM implemented the limiters.  It appears that the DSR's have a soft limit and a good measure of hysteresis to keep things sounding good even if you are stupid with them (the afore mentioned DJ gig for instance ;) ).

I still don't think pegging the input sensitivity as a matter of practice is such a good idea.

To you and Tim, yes, I used the term "VU meter" improperly.  I haven't actually seen one out in the wild for some time ;)
Title: Re: Powered Speakers
Post by: Steve M Smith on August 11, 2015, 04:20:19 AM
I still don't think pegging the input sensitivity as a matter of practice is such a good idea.

I would consider doing it for a small/quiet event in order to have the master faders in a more 'normal' position.
 
Having said that, I have done a lot of small/quiet events and have never turned down the input controls!


Steve.